I just updated my Premium Nav unit with a micro-SD card from Toyota-EU, part number PZ445-US335-0P
I paid approx 3x the price in your link but felt more comfortable to have the card from Toyota, less chance of corrupted data, or possible missing/incomplete data. I simply removed the original card and replaced with the update. When powered up it automatically updated the maps and then updated the software.
My dealer wanted £640 for the card and £30 labour to perform the update ....